The Obama administration’s official policy on U.S. military
ground forces is that they should no longer be sized for possible “large-scale
prolonged stability operations.” The policy was stated in the
administration’s 2012 Defense Strategic Guidance, and dutifully reasserted
last year in the Pentagon’s signature planning document known as the
Quadrennial Defense Review.

“Stabilization operations” can include the range of
missions spanning counterinsurgency, state-building, large-scale
counterterrorism, and large-scale relief activities conducted in anarchic
conditions. Though constraints like sequestration have limited the money
available for the U.S. military, the Obama policy calling for a smaller standing
ground army reflects a deliberate strategy shift and not just a response to
cost-cutting, since some other parts of the military are not being reduced.

It is understandable that in the aftermath of wars in Iraq and
Afghanistan, President Obama would want the military to avoid messy ground
operations in the future and rely instead on drones, commandos and other
specialized capabilities. But as a guide to long-term force planning, the order
to end America’s ability to mount such large-scale missions is dangerous. It
should be corrected by the next president before it does real harm to the
nation’s military.

There are lots of reasons to worry about the effect of the
edict. As a direct result of it, during the 2013 government shutdown standoff,
Pentagon internal budget reviews contemplated an active-duty army of only
380,000 soldiers. That would have been less than half Reagan-era levels and
almost 200,000 fewer than in the George W. Bush and early Obama years. Such a
figure would also have been 100,000 fewer than in the Clinton years, when the
world seemed somewhat safer than it does today.

Nonetheless, people such as former Chief of Naval Operations
Gary Roughead haveadvocated an
army of less than 300,000 full-time soldiers which, at least in terms of size,
would barely leave it in the world’s top 10. The U.S. Army is already smaller
than those of China, North Korea and India—even if one adds the Marine
Corps’s 180,000 active-duty forces.

Such small-is-enough thinking echoes a romantic part of
America’s past. For most of its first 150 years, the U.S. had a very modest
standing army. Until the Civil War, the figure hovered around 15,000 soldiers,
and after the war it declined to similar levels. At the turn of the 20th
century, U.S. ground forces barely ranked in the top 20 in the world in size.
After World War I they were cut back to a comparable standing, as America
consciously sought to avoid the ways and mores of the European nation-states and
their permanent militarization.

After World War II, the U.S. disbanded its armed forces so
fast that five years later, in 1950, the nation that had recently wielded the
greatest military machine in history was unable to fend off North Korean
communists attacking the South. By Vietnam the U.S. had forgotten so much about
the innate character of war that it wound up waging a counterinsurgency campaign
that overemphasized tanks, artillery, B-52s and napalm.

After Vietnam, the national revulsion against messy ground
war, combined with a fascination with precision-strike technology after
Operation Desert Storm in 1990-91, persuaded us that traditional ground
conflicts would not be repeated. As a result, the U.S. was caught off guard by
the tactical requirements of counterinsurgency operations in Iraq and
Afghanistan.

With defense budgets declining, China rising, and high-tech
frontiers beckoning, the temptation is again to put all of our strategic eggs in
the baskets of cyber operations, high-tech air and sea operations, robotics,
space technologies and special forces. All are important and should be pursued
in certain ways. But history suggests they will not be enough.

To protect core national security interests, the U.S. must
anticipate a range of possible large-scale ground operations. Some—like
scenarios involving Russia’s President Putin and aggression against the Baltic
states, or conflict between the Koreas—have more the character of classic
preparation for war. Others range from stabilization and relief missions after a
massive tragedy or Indo-Pakistani war in South Asia, to a peace enforcement
mission after a future peace deal in Syria, to a complex counterinsurgency
alongside an Ebola outbreak in a place like northern Nigeria.

In every case, deterrence would be better than having to
fight. But deterrence may fail. Each crisis could directly threaten the U.S. and
its security, and could require American forces as part of a multinational
coalition. This suggests that while the Army may not need to grow significantly,
it should not be cut further.

It is one thing for President Obama to try to avoid more
Mideast quagmires on his watch. It is quite another to direct the Army not to be
ready for the plausible range of missions that history, as well as ongoing
trends in demographics and technology and global politics, counsels us to
anticipate. In our future defense planning, we should remember the old Bolshevik
saw: You may not have an interest in war, but war may have an interest in you.